Renal and Hepatic Function in Hypercholesterolemic Rats Fed Jamaican Bitter Yam (Dioscorea polygonoides).

Background: We reported that Jamaican bitter yam (Dioscorea polygonoides) has antilipemic potential in rats; however there is limited data on the toxicological profile of the yam. We therefore investigated the effects of bitter yam consumption for 6 or 12 weeks on renal and hepatic function in rats fed a high (4%) cholesterol diet.

Methods: Twenty four rats were divided into six groups (n = 4); three of which were used for each investigation (6 or 12 weeks). One group was administered 4% cholesterol diet, while the yam group had the cholesterol diet supplemented with 5% bitter yam. The control group was fed standard rat chow. Liver and kidney function tests were performed on serum, liver and kidney. Histological studies were conducted on liver samples. Acute toxicity tests were performed in rats and mice administered a single high dose of bitter yam (10 g/kg).

Results: Activities of liver and kidney AST and ALT differed (p ≤ .02) between control rats and those fed cholesterol with bitter yam for 12 weeks. Albumin to globulin ratio was reduced (p = .03) in rats fed cholesterol with bitter yam for 6 weeks as compared to the control group. Serum urea concentration was higher (p < .05) in rats fed bitter yam as compared to normal chow for 6 weeks. The cholesterol diet caused extensive fat deposition in liver cells; however this was inhibited by co-administration of bitter yam.

Conclusion: Long-term administration of Jamaican bitter yam may induce slight changes in renal and hepatic functions.